The AFR is reporting that Macquarie has released a note downgrading Appen because they haven't released a guidance update yet.

Analysts pointed out that Appen is yet to provide a year-end guidance update that which indicates the risk of a potential downgrade.

“Appen has provided a trading update on its financial year guidance before year end over the past few years. In 2018 and 2019, the company upgraded guidance in mid-November, whereas in 2020, Appen downgraded guidance in December,” analysts said.

“The difference in timing of upgrades vs downgrades are due to Appen’s lack of earnings visibility in our view.”

Hard to know if this is a reasonable assumption: there's only three data points to base it on. The market seems to agree, though, as price is down ~13%